it, because I was afraid.'"

* * * * *

Two more members of Phillips' squad broke into the laboratory and came
toward the chief. They had been working at physical labor, for they
were still perspiring and one regarded his hands with a rueful
expression.

"Any luck?" asked Phillips eagerly.

"No, boss. We been all over the place, and we dug every spot we could
get to earth in the cellar. Most of it's three-inch concrete, without
a sign of a break."

"Did you look in the furnace?"

"We looked there the first thing. She ain't there."

There were several closets in the laboratory, and Phillips opened all
of them and inspected them. As he moved near the big plate, Lambert
uttered a cry of warning. "Don't disturb that, don't touch anything
near it!"

"All right, all right," said Phillips testily.

The skeptical sleuths had classified Lambert as a "nut," and were
practically sure he had done away with Madge Crawford because she
would not marry him.

Still, they needed better evidence than their mere beliefs. There was
no corpus delicti, for instance.

"Gentlemen," said Lambert at last, controlling his emotions with a
great effort. "I will admit to you that I am in trepidation and a
state of mental torture as to Miss Crawford's fate. You are delaying
matters, keeping me from my work."

"He thinks about work when the girl he claims he loves has
disappeared," said Doherty, in a loud whisper to Phillips. Doherty was
one of the sleuths who had been digging in the cellar, and the hard
work had made his temper short.

"You must help us find Miss Crawford before we can let you alone,"
said Phillips. "Can't you understand that you are under grave
suspicion of having injured her, hidden her away? This is a serious
matter, Professor Lambert. Your experiments can wait."

"This one cannot," shouted Lambert, shaking his fists. "You are
fools!"

"Steady now," said Doherty.

* * * * *

"Perhaps you had better come with us to the district attorney's
office," went on Phillips. "There you may come to your senses and
realize the futility of trying to cover up your crime--if you have
committed one. If you have not, why do you not tell us where Miss
Crawford is?"

"Because I do not know myself," replied Lambert. "But you can't take
me away from here. I beg of you, gentlemen, allow me a little more
time. I must have it."

Phillips shook his head. "Not unless y